The effect of lithium chloride on BDNF, NT3, and their receptor mRNA levels in the spinal contusion rat models.

OBJECTIVE: Nowadays, there seems to be no decisive way for treatment of spinal cord injury (SCI).Extensive cell death (apoptosis and necrosis) occurring in SCI can cause considerable progressive sensorimotor disabilities. Preventing cell death by improving endogenous regenerative capability could an effective strategy for the treatment of SCI. This study was designed to evaluate the effects of lithium chloride (LiCl) on the cell survival through overexpression of BDNF and NT3 mRNA level and their receptors in the contusion rat models.

METHODS: Rats were randomly divided into four experimental groups (eight rats/group) including: contused animals (the non-treatment group); contused animals (the control group) which received laminectomy; contused animals received normal saline (vehicle)and contused animals received intraperitoneal injection of 20 mg/kg LiCl three days after surgery. Injection continued for 14 days as treatment. Basso, Beattie, Bresnahan (BBB) rating scale was used to assess the motor function of the rats. To evaluate the histopathological and gene expression analysis, rats were sacrificed 28 days after surgery. Real-time reverse transcriptase polymerase chain reaction (RT-PCR) was performed to obtain the relative levels of mRNA for BDNF, NT3 and their receptors.

RESULTS: The results showed LiCl ameliorates BBB scores via up-regulation of BDNF and TrkB receptors. Also, histological analysis showed that the numerical density per area of TUNEL- positive cells and the percentage of cavity significantly decreased in the LiCl-treated group.

CONCLUSION: Our findings suggest that LiCl protects neural cells and effectively enhances locomotor function, which was done through up-regulation of endogenous BDNF expression in rats with SCI.

ABBREVIATIONS: SCI: spinal cord injury; LiCl: lithium chloride; BDNF: Brain-derived neurotrophic factor; NT3: Neurotrophin-3; BBB: Basso, Beattie, Bresnahan; TrkB: Tropomyosin receptor kinase B; TUNEL: Terminal deoxynucleotidyl transferase dUTP nick end labeling.